[v2] media: uapi: v4l: Change V4L2_TYPE_IS_CAPTURE condition

[PATCH v2] media: uapi: v4l: Change V4L2_TYPE_IS_CAPTURE condition

Posted by Nas Chung 1 year, 8 months ago

Explicitly compare a buffer type only with valid buffer types,
to avoid matching the buffer type outside of valid buffer
type set.

Signed-off-by: Nas Chung <nas.chung@chipsnmedia.com>
---
 include/uapi/linux/videodev2.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index fe6b67e83751..fa2b7086e480 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -157,6 +157,10 @@ enum v4l2_buf_type {
 	V4L2_BUF_TYPE_PRIVATE              = 0x80,
 };
 
+#define V4L2_TYPE_IS_VALID(type)		\
+	((type) >= V4L2_BUF_TYPE_VIDEO_CAPTURE	\
+	 && (type) <= V4L2_BUF_TYPE_META_OUTPUT)
+
 #define V4L2_TYPE_IS_MULTIPLANAR(type)			\
 	((type) == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE	\
 	 || (type) == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
@@ -171,7 +175,8 @@ enum v4l2_buf_type {
 	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
 	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
 
-#define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
+#define V4L2_TYPE_IS_CAPTURE(type)	\
+	(V4L2_TYPE_IS_VALID(type) && !V4L2_TYPE_IS_OUTPUT(type))
 
 enum v4l2_tuner_type {
 	V4L2_TUNER_RADIO	     = 1,
-- 
2.25.1

Re: [PATCH v2] media: uapi: v4l: Change V4L2_TYPE_IS_CAPTURE condition

Posted by Sebastian Fricke 1 year, 8 months ago

Hey Nas,

just before you send out V3 ...

On 28.05.2024 11:04, Nas Chung wrote:
>Explicitly compare a buffer type only with valid buffer types,
>to avoid matching the buffer type outside of valid buffer
>type set.

s/matching the buffer type outside of valid buffer type set/
   matching a buffer type outside of the valid buffer type set/

Regards,
Sebastian

>Signed-off-by: Nas Chung <nas.chung@chipsnmedia.com>
>---
> include/uapi/linux/videodev2.h | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>index fe6b67e83751..fa2b7086e480 100644
>--- a/include/uapi/linux/videodev2.h
>+++ b/include/uapi/linux/videodev2.h
>@@ -157,6 +157,10 @@ enum v4l2_buf_type {
> 	V4L2_BUF_TYPE_PRIVATE              = 0x80,
> };
>
>+#define V4L2_TYPE_IS_VALID(type)		\
>+	((type) >= V4L2_BUF_TYPE_VIDEO_CAPTURE	\
>+	 && (type) <= V4L2_BUF_TYPE_META_OUTPUT)
>+
> #define V4L2_TYPE_IS_MULTIPLANAR(type)			\
> 	((type) == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE	\
> 	 || (type) == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
>@@ -171,7 +175,8 @@ enum v4l2_buf_type {
> 	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
> 	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
>
>-#define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
>+#define V4L2_TYPE_IS_CAPTURE(type)	\
>+	(V4L2_TYPE_IS_VALID(type) && !V4L2_TYPE_IS_OUTPUT(type))
>
> enum v4l2_tuner_type {
> 	V4L2_TUNER_RADIO	     = 1,
>-- 
>2.25.1
>

Re: [PATCH v2] media: uapi: v4l: Change V4L2_TYPE_IS_CAPTURE condition

Posted by Hans Verkuil 1 year, 8 months ago

On 28/05/2024 04:04, Nas Chung wrote:
> Explicitly compare a buffer type only with valid buffer types,
> to avoid matching the buffer type outside of valid buffer
> type set.
> 
> Signed-off-by: Nas Chung <nas.chung@chipsnmedia.com>
> ---
>  include/uapi/linux/videodev2.h | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index fe6b67e83751..fa2b7086e480 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -157,6 +157,10 @@ enum v4l2_buf_type {
>  	V4L2_BUF_TYPE_PRIVATE              = 0x80,
>  };
>  
> +#define V4L2_TYPE_IS_VALID(type)		\
> +	((type) >= V4L2_BUF_TYPE_VIDEO_CAPTURE	\
> +	 && (type) <= V4L2_BUF_TYPE_META_OUTPUT)
> +
>  #define V4L2_TYPE_IS_MULTIPLANAR(type)			\
>  	((type) == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE	\
>  	 || (type) == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
> @@ -171,7 +175,8 @@ enum v4l2_buf_type {
>  	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
>  	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
>  
> -#define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
> +#define V4L2_TYPE_IS_CAPTURE(type)	\
> +	(V4L2_TYPE_IS_VALID(type) && !V4L2_TYPE_IS_OUTPUT(type))
>  
>  enum v4l2_tuner_type {
>  	V4L2_TUNER_RADIO	     = 1,

This patch introduced this warning:

In function 'find_format_by_index',
    inlined from 'vdec_enum_fmt' at drivers/media/platform/qcom/venus/vdec.c:452:8:
drivers/media/platform/qcom/venus/vdec.c:172:32: warning: 'valid' may be used uninitialized [-Wmaybe-uninitialized]
  172 |                 if (k == index && valid)
      |                     ~~~~~~~~~~~^~~~~~~~
drivers/media/platform/qcom/venus/vdec.c: In function 'vdec_enum_fmt':
drivers/media/platform/qcom/venus/vdec.c:157:22: note: 'valid' was declared here
  157 |                 bool valid;
      |                      ^~~~~

This driver does this:

	bool valid;

        if (V4L2_TYPE_IS_OUTPUT(type)) {
                valid = venus_helper_check_codec(inst, fmt[i].pixfmt);
        } else if (V4L2_TYPE_IS_CAPTURE(type)) {
                valid = venus_helper_check_format(inst, fmt[i].pixfmt);

With your patch both V4L2_TYPE_IS_OUTPUT(type) and V4L2_TYPE_IS_CAPTURE(type)
can return false, something that wasn't possible without this patch.

In this driver the fix would just be to drop the second 'if' altogether, so just
'} else {'.

Since these defines are part of the public API, this change introduces a subtle
behavior difference that can affect applications.

That said, I do consider this an improvement.

I would like some changes, though:

1) Just after "V4L2_BUF_TYPE_META_OUTPUT          = 14," in enum v4l2_buf_type,
   add a comment saying that V4L2_TYPE_IS_VALID and (for output types)
   V4L2_TYPE_IS_OUTPUT must be updated if a new type is added. It's all
   too easy to forget that otherwise.
2) Add a patch fixing the venus/vdec.c code.
3) Something else I noticed, but I think this change should be in a separate patch:
   V4L2_TYPE_IS_OUTPUT() returns true for V4L2_BUF_TYPE_VIDEO_OVERLAY, but that
   definitely belongs to CAPTURE. Nobody really uses that type anymore, but still,
   it should be fixed.

Regards,

	Hans

Re: [PATCH v2] media: uapi: v4l: Change V4L2_TYPE_IS_CAPTURE condition

Posted by Michael Tretter 1 year, 8 months ago

On Tue, 28 May 2024 11:04:25 +0900, Nas Chung wrote:
> Explicitly compare a buffer type only with valid buffer types,
> to avoid matching the buffer type outside of valid buffer
> type set.
> 
> Signed-off-by: Nas Chung <nas.chung@chipsnmedia.com>

Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>

> ---
>  include/uapi/linux/videodev2.h | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index fe6b67e83751..fa2b7086e480 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -157,6 +157,10 @@ enum v4l2_buf_type {
>  	V4L2_BUF_TYPE_PRIVATE              = 0x80,
>  };
>  
> +#define V4L2_TYPE_IS_VALID(type)		\
> +	((type) >= V4L2_BUF_TYPE_VIDEO_CAPTURE	\
> +	 && (type) <= V4L2_BUF_TYPE_META_OUTPUT)
> +
>  #define V4L2_TYPE_IS_MULTIPLANAR(type)			\
>  	((type) == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE	\
>  	 || (type) == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
> @@ -171,7 +175,8 @@ enum v4l2_buf_type {
>  	 || (type) == V4L2_BUF_TYPE_SDR_OUTPUT			\
>  	 || (type) == V4L2_BUF_TYPE_META_OUTPUT)
>  
> -#define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
> +#define V4L2_TYPE_IS_CAPTURE(type)	\
> +	(V4L2_TYPE_IS_VALID(type) && !V4L2_TYPE_IS_OUTPUT(type))
>  
>  enum v4l2_tuner_type {
>  	V4L2_TUNER_RADIO	     = 1,
> -- 
> 2.25.1
> 
>